1. Field of the Invention
The present invention relates generally to filters and, more specifically, to an air induction filter assembly for both automotive and non-automotive air intake applications.
2. Description of the Related Art
It is known to provide an air induction filter for an engine of a motor vehicle to filter out contaminants in air entering the engine. In the past, the air induction filter was typically made of pleated paper housed in a plastic or metal frame. The air induction filter and frame were mounted in an engine compartment of the motor vehicle. These air induction filters were used once and discarded.
Currently, the reticulated foam filter is typically made of a foam material and housed in a plastic housing made out of glass filled nylon due to the high temperatures in the engine compartment. The foam material is several layers thick. An example of such an air induction filter is disclosed in U.S. Pat. No. 5,437,701. In this patent, the air induction filter has a molded or extruded housing which contains several layers of filter material. The layers can be either relatively thin or thick and treated or untreated. If the layer is treated, it contains an additive such as oil.
It is also known that virtually all components in the motor vehicle contribute to evaporative emissions. It has been established that there is a significant amount of hydrocarbon vapors (15 mg of gasoline per injector) in a range of about 150 to 300 mg per day escaping through an air inlet of the engine as measured by a shed test known in the art. These emissions are emitted by raw fuel in the inlet manifold and some leakage through the injectors.
Therefore, it is desirable to provide an air induction filter that will adsorb some of the hydrocarbon vapors. It is also desirable to provide an air induction filter that will control contaminants entering the engine and will remove hydrocarbon vapors exiting from the engine at the same time. It is desirable to provide an air induction filter that has 150,000 miles of service for automotive applications and extended service life for non-automotive applications. It is further desirable to provide an air induction filter that will not require servicing up to 150,000 miles under normal driving conditions. Therefore, there is a need in the art to provide an air induction filter assembly that meets these desires.
Accordingly, the present invention is an air induction filter assembly including a housing and a filter disposed in the housing. The filter has a plurality of layers with one of the layers being a carbon impregnated foam layer to remove residual hydrocarbon (HC) vapors diffusing through an air inlet to the filter.
One advantage of the present invention is that a new air induction filter assembly is provided for an engine of a motor vehicle. Another advantage of the present invention is that the air induction filter assembly uses reticulated multi-layered foam with carbon impregnation to remove residual hydrocarbon (HC) vapors diffusing through the inlet manifold of the engine after the engine is shut-off. Yet another advantage of the present invention is that the air induction filter assembly will control contaminants and hydrocarbon vapors at the same time. Still another advantage of the present invention is that the air induction filter assembly has a long life and may require no changing or servicing up to 150,000 miles under normal driving conditions. A further advantage of the present invention is that the air induction filter assembly has low restriction of the carbon impregnated layer, which protects against shedding of carbon particles, i. e. the carbon is contained. Yet a further advantage of the present invention is that the air induction filter assembly has a carbon impregnated layer that is protected against dust, water and snow. Still a further advantage of the present invention is that the air induction filter assembly has reduced weight, cost, parts and complexity. Another advantage of the present invention is that the air induction filter assembly has packaging flexibility (shape and size) and can be packaged outside an engine compartment of the motor vehicle. Yet another advantage of the present invention is that the air induction filter assembly has lower inlet air temperatures, resonator requirements, and noise.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood after reading the subsequent description when taken in conjunction with the accompanying drawings.